SVC cluster configuration node failover

1. A failover method for responding to configuration node failures in a SAN Volume Controller (SVC) cluster, wherein the SVC cluster manages a plurality of storage devices and comprises a plurality of SVCs interconnected via the internet, each SVC acting as a separate node, and at any given time, only one node within the SVC cluster functions as a configuration node to operate external services, the method comprising: setting an entry to a positive value indicating a storage device event has been handled after an original configuration node notifies respective subscribed clients about storage device events the original configuration node receives.

2. The method according to claim 1 , further including performing one of: making the entry in a storage device event log each time the original configuration node receives storage device events and setting the entry to a negative value indicating a storage device event has not been handled, saving, with the original configuration node, the storage device event log, activating a new configuration node in response to failures of the original configuration node, wherein any entries in the storage device event log contains at least the following information: an event code; an event description; and an indication as to whether that event has been handled.

3. The method according to claim 1 , performing the following: obtaining client subscription information related to the storage device events managed by the SVC cluster from the plurality of storage devices with a new configuration node, wherein the plurality of storage devices are not in the original configuration node, retrieving the storage device events from a storage device event monitoring unit with the new configuration node in response to the storage device events occurring in the plurality of storage devices managed by the SVC cluster, and sending storage device events to subscribed clients with the new configuration node based on the obtained client subscription information.

4. The method according to claim 3 , wherein the storage device event monitoring unit is in a node other than the original configuration node of the SVC cluster.

5. The method according to claim 4 , wherein any of the entries in a storage device event log further includes a time of event occurrence.

6. The method according to claim 5 , further comprising: with an original configuration node, making an entry in the storage device event log each time the original configuration node receives a storage device event and recording the time at which the storage device event occurs for the time of event occurrence.

7. The method according to claim 6 , further comprising: recording the time at which a failure of the original configuration node occurs in response to the failure of the original configuration node, recording successful activation of the new configuration node in response to a successful activation of the new configuration node, determining which events in the storage device event log occurred between the failure time of the original configuration node and a successful activation time of the new configuration node based on the failure time of the original configuration node and the successful activation time of the new configuration node, searching for subscribed clients for the events that occurred between the failure time of the original configuration node and the successful activation time of the new configuration node based on the obtained client subscription information stored in one of the plurality of storage devices, and sending corresponding events to the searched for subscribed clients for the events that occurred between the failure time of the original configuration node and the successful activation time of the new configuration node.

8. The method according to claim 1 , further comprising: with a new configuration node, searching for entries that are set to a negative value indicating the storage device event has not been handled in a storage device event log after activation, searching for subscribed clients who have subscribed to events corresponding to all records based on obtained client subscription information, and sending the corresponding events to clients who have subscribed to these events.

9. A failover system for responding to configuration node failures in a SAN Volume Controller (SVC) cluster, the SVC cluster managing a plurality of storage devices and comprising a plurality of SVCs interconnected via the internet, each SVC acting as a separate node, and at any given time, only one node within the SVC cluster functioning as a configuration node to operate external services, the system comprising: a storage device sets an entry to a positive value indicating a storage device event has been handled after an original configuration node notifies respective subscribed clients about storage device events the original configuration node receives.

10. The failover system according to claim 9 , further including at least one of: the storage device to make the entry in a storage device event log each time the original configuration node receives storage device events and setting the entry to a negative value indicating a storage device event has not been handled, the storage device to save, with the original configuration node, the storage device event log, and an activation unit to activate a new configuration node in response to node failures of the original configuration node, wherein any entries in the storage device event log contains at least the following information: an event code; an event description; and an indication as to whether that event has been handled.

11. The failover system according to claim 9 , further including: a storage device to store client subscription information regarding the storage device events managed by the SVC cluster, and the storage device is not in the original configuration node, a storage device event monitoring unit to monitor the plurality of storage devices managed by the SVC cluster, a first retrieval unit to enable a new configuration node to retrieve the client subscription information from the plurality of storage devices, a second retrieval unit to enable the new configuration node to retrieve a storage device event from the storage device event monitoring unit, and a submission device to enable the new configuration node to send the storage device event to subscribed clients based on the client subscription information.

12. The failover system according to claim 11 , wherein the storage device event monitoring unit is in a node other than the original configuration node of the SVC cluster.

13. The failover system according to claim 9 , wherein following activation of a new configuration node, the new configuration node searches for all entries that are set to a negative value indicating the storage device event has not been handled, searches for the subscribed clients who have subscribed to events corresponding to the entries that are set to a negative value indicating the storage device event has not been handled based on client subscription information, and sends the corresponding events to the respective subscribed clients.

14. The failover system according to claim 9 , wherein any entries in a storage device event log contains a time of event occurrence.

15. The failover system according to claim 14 , wherein the storage device event monitoring unit of the original configuration node makes an entry in the storage device event log every time the storage device event monitoring unit receives a storage device event and records the time at which the storage device event occurred for the time of event occurrence.

16. The failover system according to claim 15 , wherein: when an activation unit monitors a failure of the original configuration node, the activation unit records the time at which the failure of the original configuration node occurs, a new configuration node records the successful activation time of the new configuration node following successful activation of the new configuration node, and the new configuration node determines which events in the storage device event log occurred between the failure time of the original configuration node and a successful activation time of the new configuration node based on the failure time of the original configuration node and the successful activation time of the new configuration node and searches for subscribed clients for the events that occurred between the failure time of the original configuration node and the successful activation time of the new configuration node based on the subscription information stored in the storage device and corresponding events to the searched for subscribed clients for the events that occurred between the failure time of the original configuration node and the successful activation time of the new configuration node.

17. A computer program product for responding to configuration node failures in a SAN Volume Controller (SVC) cluster, the computer program product comprising a non-transitory computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising: a first executable portion that sets an entry to a positive value indicating a storage device event has been handled after an original configuration node notifies respective subscribed clients about storage device events the original configuration node receives.

18. The computer program product according to claim 17 , further including a second executable portion that performs one of: making the entry in a storage device event log each time the original configuration node receives storage device events and setting the entry to a negative value indicating a storage device event has not been handled, saving, with the original configuration node, the storage device event log, and activating a new configuration node in response to failures of the original configuration node, wherein any entries in the storage device event log contains at least the following information: an event code; an event description; and an indication as to whether that event has been handled.

19. The computer program product according to claim 17 , further comprising a second executable portion that performs the following: obtaining client subscription information related to the storage device events managed by the SVC cluster from the plurality of storage devices with a new configuration node, wherein the plurality of storage devices are not in the original configuration node, retrieving the storage device events from a storage device event monitoring unit with the new configuration node in response to the storage device events occurring in the plurality of storage devices managed by the SVC cluster, and sending storage device events to subscribed clients with the new configuration node based on the obtained client subscription information.

20. The computer program product according to claim 19 , wherein the storage device event monitoring unit is in a node other than the original configuration node of the SVC cluster.

21. The computer program product according to claim 20 , wherein any entries in a storage device event log further includes a time of event occurrence.

22. The computer program product according to claim 21 , further comprising a second executable portion that, with original configuration node, makes an entry in the storage device event log each time the original configuration node receives a storage device event and recording the time at which the storage device event occurs for the time of event occurrence.

23. The computer program product according to claim 22 , further comprising a third executable portion that performs the following: recording the time at which a failure of the original configuration node occurs in response to the failure of the original configuration node, recording successful activation of the new configuration node in response to a successful activation of the new configuration node, determining which events in the storage device event log occurred between the failure time of the original configuration node and a successful activation time of the new configuration node based on the failure time of the original configuration node and the successful activation time of the new configuration node, searching for subscribed clients for the events that occurred between the failure time of the original configuration node and the successful activation time of the new configuration node based on the obtained client subscription information stored in one of the plurality of storage devices, and sending corresponding events to the searched for subscribed clients for the events that occurred between the failure time of the original configuration node and the successful activation time of the new configuration node.

24. The computer program product according to claim 17 , further comprising a second executable portion that performs the following: with a new configuration node, searching for entries that are set to a negative value indicating the storage device event has not been handled in a storage device event log after activation, searching for subscribed clients who have subscribed to events corresponding to all records based on obtained client subscription information, and sending the corresponding events to clients who have subscribed to these events.